1. Technical Field
This disclosure generally relates to an image forming apparatus that forms an image by a recording head which ejects ink droplets of recording liquid.
2. Description of the Related Art
As an image forming apparatus such as a printer, a facsimile, a copying apparatus, and a multifunctional apparatus that has the above functions, an apparatus which uses an electro-photographic system for forming an image is widely known. In addition, there is an image forming apparatus which uses an inkjet system for forming an image. In the inkjet system, a recording head composed of ink droplet ejecting heads which eject ink droplets of recording liquid is used, and an image is formed on a recording medium (paper) by ejecting the ink droplets of the recording liquid onto the recording medium from the recording head while carrying the recording medium. In this, the recording medium is not limited to a paper, and any other recording medium such as an image transferring medium can be used as the recording medium; and as the image forming, image recording, image printing, letter printing, and so on are included.
In Patent Document 1, a conventional inkjet recording apparatus is disclosed. The inkjet recording apparatus includes a recording liquid supplying mechanism of a sub ink tank type in which a recording head unit and sub ink tanks that supply recording liquid to recording heads are provided in a carriage.
In Patent Document 2, another conventional inkjet recording apparatus is disclosed. In the inkjet recording apparatus providing a recording liquid supplying mechanism using a tube that supplies recording liquid to a recording head, the recording head is easily changed. In order to easily handle the tube and to change only members to be required when the recording head is changed, the recording head is removably attached to a carriage and a connector holding the tube is removably attached to the recording head.
In Patent Document 3, another conventional inkjet recording apparatus is disclosed. In the inkjet recording apparatus, each of recording heads is separately changed. When plural ink supplying tubes are connected to the plural recording heads or sub ink tanks disposed in a carriage, the tubes are held via a holding member that provides a hole without having a notch and holes having a notch.
In Patent Document 4, another conventional inkjet recording apparatus is disclosed. In the inkjet recording apparatus, a recording head is easily changed. The inkjet recording apparatus provides a carriage formed by a different member from a sub ink tank, the sub ink tank, and a recording head which is removably attached to the sub ink tank, and the sub ink tank has a suction opening which opens only at a predetermined time when being suctioned from the outside, with this, an ink supplying mechanism is simplified.
In Patent Document 5, a conventional inkjet printer of a module type is disclosed. In the inkjet printer, one end of a tube is connected to a recording head and the other end of the tube is connected to an ink reservoir, and plural ink reservoirs are installed in a housing. Then, the recording head, the tube, and the ink reservoir are removed as one unit.
In Patent Document 6, a conventional inkjet printer is disclosed. The inkjet printer does not have a recording liquid tube for supplying recording liquid to a recording head. However, in order to miniaturize the printer and to have high maintainability, a carriage moving space is formed between right and left frame side plate members and a recording paper carrying section is disposed in the front of the printer and an ink supplying section is disposed in the back of the printer. A head maintenance unit is disposed in a space at the rear side part and the side part of the recording paper carrying section. The head maintenance unit and a recording paper carrying unit are removably attached to the right and left side frame plate members.
[Patent Document 1] Japanese Laid-Open Patent Application No. 2002-001983
[Patent Document 2] Japanese Laid-Open Patent Application No. 2003-211700
[Patent Document 3] Japanese Laid-Open Patent Application No. 6-344626
[Patent Document 4] Japanese Laid-Open Patent Application No. 5-124214
[Patent Document 5] Japanese Translation of PCT International Application No. 2002-506758 (WO 99/47355)
[Patent Document 6] Japanese Laid-Open Patent Application No. 2002-273861
However, as described above, in Patent Documents 1 and 4, in the structure in which the recording liquid is supplied from a recording liquid storing unit to the recording head or the sub ink tank by using the recording liquid tube, the recording head is easily exchanged by making the connection and the disconnection between the recording head and the recording liquid tube easy. However, in some cases, the inkjet recording apparatus does not work normally after exchanging the recording head due to air or dust entering in the recording liquid tube when removing the recording liquid tube.
In Patent Document 5, the recording head, the tube, and the ink reservoir are removed as one unit; therefore, there is no need to remove only the tube. However, when the ink in the ink reservoir is used up, all of the recording head, the tube, and the ink reservoir must be removed and this results in a high cost. In a case where only the ink reservoir is removed, the ink reservoir and the tube are disconnected and air or dust may enter the tube. Consequently, the inkjet printer may not work normally after exchanging the recording head.